1. Field of the Disclosure
The present disclosure relates to a rotary connector that can transmit an electrical signal or the like between a stationary body and a rotating body, and more particularly, to a rotary connector where a planetary gear is interposed between a stationary housing and a movable housing so that the stationary housing and the movable housing are rotatable relative to each other.
2. Description of the Related Art
A rotary connector is used in an automobile and the like to transmit an electrical signal or an optical signal or supply power between a stationary body and a rotating body. Specifically, when an air bag is provided in a steering wheel or switches used to operate an audio system and the like are provided on the steering wheel, electrical communication or the like needs to be performed between the steering wheel, which is a rotating body, and a vehicle that is a stationary body. For this purpose, a rotary connector is installed on the steering wheel.
A stationary housing, which is provided on the stationary body, and a movable housing, which is provided on the rotating body, of the rotary connector are disposed coaxially. An annular space portion is formed between an outer cylindrical body formed at the stationary housing and an inner cylindrical body formed at the movable housing, and a flat cable is wound and received in the annular space portion. Both end portions of the flat cable are connected to the stationary housing and the movable housing, respectively. When the movable housing is rotated as the rotating body is rotated, the flat cable is wound or unwound. Accordingly, the rotary connector maintains electrical connection between the stationary body and the rotating body, regardless of the rotation of the rotating body.
In such a rotary connector, it is possible to make the length of the flat cable, which is required to obtain the same rotatable range of the rotary connector, short by reversing the flat cable while winding the flat cable this type of rotary connector, there is a rotary connector disclosed in Japanese Unexamined Utility Model Registration Application Publication No. 6-50283.
A rotary connector where a flat cable is made short by reversing the flat cable employs a structure where an internal gear (outer gear) is formed at a stationary housing, a sun gear is formed at a movable housing, the internal gear and the sun gear face each other, a planetary gear meshing with both the internal gear and the sun gear is provided, and the planetary gear is provided with a reverse maintaining portion for maintaining a state where the flat cable is reversed.
However, in this case, a certain amount of backlash is required between the planetary gear and the internal gear and between the planetary gear and the sun gear in order to perform a smooth operation even in consideration of the deformation of the gears and the like. For this reason, since the gears collide with each other and rattle when the automobile vibrates and the like, rattling noises are caused.